A volcano erupts, depositing 12 million cubic metres of lava over an area of 40 km². Calculate the average thickness of the lava flow in metres and discuss how such a thickness could influence local agriculture.

Step-by-step solution

1. Convert area to m²: $40{\text{ km}}^2=40\times 10^6{\text{ m}}^2$.
2. Divide the lava volume by the area: $12\times 10^6{\text{ m}}^3÷40\times 10^6{\text{ m}}^2=0.3\text{ m}$.
3. Explain that a 0.3‑m thick lava layer can smother existing vegetation, cover fertile soil, and increase erosion, thereby negatively impacting local agriculture.

Concept tested: Lava flow thickness and agricultural impact

Published 16 October 2026 · How this solution was prepared and checked